Example 2 [1]}
For \(x \in [m_1, m_2],\)  the function
\(\mathcal {G}(x)=\left\lbrace \begin{array}{ll}{1,} & {m_1 \le x<\frac{m_1+m_2}{2}} \\ {4,} & {x=\frac{m_1+m_2}{2}} \\ {1,} & {\frac{m_1+m_2}{2}<x \le m_2}\end{array}\right.\) 
